Recent Articles

It's a lot of other things, but mostly huge. If you lose your keys in it, you're pretty much screwed.

NASA has a lot of ground to cover in its search for alien life. The agency made some progress recently by successfully demonstrating in the laboratory the technology behind its next space telescope designed to find planets similar to home sweet home. A panel of NASA scientists shared the news today at a press meeting at the SETI Institute in Mountain View.

Scientists currently have a census of over 200 Jupiter-sized planets orbiting near stars, but no real idea how common Earth-size planets are. NASA Ames's Jack Lissauer explains the focus on the big boys isn't because gas giants are the most common but because they're most easily detectable with today's equipment.

"It would be like looking from a distance at a street light at night and concluding most of the insects in the area are moths. There could be far more gnats flying around but you couldn't know."

And, if we want to search for life, we need to stick to where we think it can flourish.

Life as we know it is picky. To sustain it, a planet must orbit within a narrow band of distance from a star where water won't be permanently frozen or evaporated called the habitable zone.

Size also counts. If a planet is too small, it won't be able to hold an atmosphere well. The larger a planet, the higher its gravitational field; attracting more celestial bodies to itself and also affecting its ability to regulate atmospheric CO2.

Earth might have won the galactic lottery being the right size, material and position to sustain life — or maybe it's as common as snot.

Kepler will essentially be humanity's first scan of the cosmos' housing market. It won't send back beautiful Hubble-like pictures, and it won't detect other lifeforms — but it can tell us if we're surrounded by potential Earths or mostly alone.

Here's where the science comes in:

The best way to detect a small, earth-like planet outside our solar system is to catch it when the planet crosses the path of its parent star. By detecting the minute light disparity from the star when this occurs, we can calculate the planet's size and distance. Because a distant planet is 10 billion times fainter than the star, this is no easy endeavor. There's also no telling whether a planet will even orbit in front of the star from the angle we are viewing.

Kepler's secret sauce is its ability to watch a large piece of infinity at once. The space telescope will scan the same plot of cosmic real-estate with around 100,000 stars for four years. The Kepler team hopes the results will justify further funding to extend the time to six years.

Although most working on the Kepler project hope to find several Earth-like planets, there's certainly no guarantee.

"One of the most interesting things we could find is zero," NASA scientist William Boruki said. "That could mean we are alone in the universe."

NASA estimates the project will cost $600m. It's planned to launch in November of 2008, but, as space agency observers keeping score will note, that date is subject to change. Even the scientists at the meeting were skeptical.

"Let's just say I haven't bought the plane ticket yet," senior research scientist at McDonald Observatory William Cochran said.

The team sees Kepler as an important step in the search for alien life. Before NASA can take a closer look, it needs perspective — and there's a lot of perspective to be had in space. The agency will need to know how far they have to look and how many stars it will have to search before it can expect to find an Earth-like planet to further investigate.